An attempt has been made to delineate the cognitive deficits and changes that are associated with Huntington's Disease. It has been known for some time that Huntington's patients show clearly discernible cognitive memory deficits. The nature of this deficit and its mechanism has been poorly understood and not seriously investigated to date. We have designed a number of studies which provide us with a vehicle for examining in a systematic way the cognitive changes associated with this disorder, and also contrast these changes with other forms of dementia, for example, in Korsakoff's psychosis, temporal lobe disorder, and senile states. This project is designed to not only further our understanding of some of the memory changes in Huntington's patients, but also should begin to provide a picture of the differences and similarities to other forms of dementia. In addition, these research efforts should prove helpful in clarifying some important issues in our understanding of normal memory processes.